Circuit breaker



April 3, 1934. L, 5 KlNG 1,953,615

CIRCUIT BREAKER IVM/@mor Lloyd EKmg.

Harney Patented Apr. 3, 1934 UNITED STATES CIRCUIT BBEAKER Lloyd E. King, Berwyn, lll. originan application .my ss, ma, serial No.

853,200. Divided and this a, m1. serial No. m

is claim.

My invention relates to an improved construction of circuit breaker adapted for use particularly in connection with the electric protective systems shown in my co-pending application Berial No. 653,200, illed July 23, 1923 which became Patent No. 1.792.310 on February 10, 1981 of which this is a divisional application.

My improved circuit breaker construction is preferably provided with a plurality of tripping lo coils, to the end that the circuit breaker construction may be responsive independently to any of a plurality of controlling conditions establlished by various abnormal conditions of the conductors or systems with which the circuit breaker construction is to be employed as a protective device. For example, one of the tripping coils may respond to a condition of overload, another of the tripping coils may respond to an unbalanced electrical condition between the conductors of the protected system, another tripping coil may respond to a low voltage condition in the protected system, and so on for any conditions of abnormality which are to be protected against. Furthermore,rthe protection afforded by my construction may be against either abnormal current conditions, abnormal voltage conditions, or both, as well as pha'se reversal and any other abnormal conditions 'which may arise in the protected system.

My improved circuit breaker construction is preferably of the single pole type and includes an arrangement for blowing out the arc due to the opening of the breaker contacts, and preferably also auxiliary devices for maintaining the tripping coil or tripping coils in closed circuitcondition until the main breaker contacts are opened. after which the trippinl cOii or tripping coils are open circuited. My improved circuit breaker construction is preferably arranged for ready insertion and removal in the circuit it is to protect. for example in the manner common with enclosed cartridge fuses, and its construction is relatively simple, facilitating the use of spare circuit breakers, so that the circuit breakersmaybereadilyremovedandreplacedbyspare circuit breakers without interrupting the aerviow application January .586

(Cl. 20G-106) I'ilg. 3 is a side elevation of my circuit breaking mechanism in its released condition,

Fig.4showsinaviewsimilartoFig.1amodi-' fled construction of the upper portion of the circuit breaking mechanism,

Fig. 5 shows in a view similar to Fig. 2, a modihed form of circuit breaker mechanism using a plurality of tripping coil circuit breaking mechanisms instead of but one of the latter mechanismsasshowninligs. land 2.and

Fig. 6 is a bottom view.of the commotion shown in Fig. 5.

Similar numerals refer to similar parts throughout the several views.

As shown in Figs. 1-3 inclusive my unit circuit breaker construction consists of a tube 10 of insulating material in which a metal plunger 11 is mounted to move longitudinally. The tube l0 carries at one end an cuter metallic sleeve 12 having its outer end inturned to form a main contact or contacts 12a of the device, engaged by the plunger 11 in its set position. The inner end of the contact 12a carries a ring 13 of refractory conducting material, for example carbon, extending beyond the end of the contact, so that the break in the circuit, when the plunger 11 is withdrawn from the contact. is between the end of the plunger and the ring 13. The end of the plunger as indicated at 11a is chamfered somewhat. so that the principal arcing that occurs will be between the extreme'end of the plunger and the ring 13, and thus the pitting that would otherwise occur on the main contact surface of the plunger, is restricted to the end portion and does not roughen the contact portion of the plunger.

The sleeve 12 has mounted thereon and insulated therefrom a tripping coil 14 with its outer end nearly in the plane of the end of the tube 10 which is adjacent the arcing plane of the ring i3. The tripping coil 14 may consist of one or more sections. or coils, each capable of releasing the circuit breaker mechanism, as will be described below. The coil 14 is provided with heads 14a of magnetic material. for example soft iron. to act uponl the armature 1 5, also of magn'etic material, in a manner to 'be' described. The other end of the tube 10 has mounted therein a metal sleeve 18 in sliding contact with the plunger 11 to constitute the other main contact of the device. The sleeve 16 is provided with an outer end flange which is extended to form a bracket i7 serving as a support for the pivot 18 of the arm i9 carrying the amature 15. serving also by its rearward extension to form a connecting and mounting clip or clips 20. as more clearly shown in Fig. 3, and also serving to in part support, by means of an annular flange 2i carried thereby, an auxiliary breaker to be described. The sleeve l2 carries on its outer end a second izo y metal sleeve 22 closed at its outer end and perforated as indicated at 22a and having a lateral extension or extensions 23 to form a connecting and mounting clip or clips for the device. The clips 20 and 23 by their electrical connection with the contacts 16 and 12a respectively, constitute the main connections of the circuit breaker to the circuit to be protected thereby, and these clips may engage suitable bolts or jaws connected with the conductors forming part of the protected circuit. as a result of which the device as a whole may be readily connected in the circuit and readily removed therefrom as may be necessary or desirable. VThese clips may have any convenient form and construction, the only desiderata being that they shall make good contact with the terminals of the protected circuit and be capable of ready connection therewith and ready disconnection therefrom.

The plunger 11 has rigidly connected with its lower end, a laterally extending arm 24, preferably of metal, and between the said arm and the outer end of the contact sleeve 18, the plunger carries a metal sleeve 25 provided at its outer end with a flange 25a engaging one end of a spring 26, the other end of which rests against the flanged outer end of the contact sleeve 16. The flanged end 25a is extended on one side of the plunger, to form a support for a pivotal connection 27 engaging one end of a nrst link 28, which is pivotally connected at its other end, as indicated at 29, with one end of a second link 30, the other end of which is pivotally connected at 31 with a downwardly projecting arm 32 carried by the bracket 17. For the closed position of the circuit breaker shown in Fig. 1, the plunger ll is in engagement with the contact 12a, the spring 26 is compressed, and the links 28 and 30 occupy a position preventing the spring from moving the plunger out of the contact 12a, since the line of pull through the pivotal connections 27 and 29 is slightly to the right, for the position of the parts shown in Fig. l. of the pivotal connection 31. The links 28 and 30 are prevented from moving around to the right,for the position of the parts shown in Fig. 1, by a suitable stop. which, as shown, may conveniently consist of an ear 32a bent from the edge portion of the arm 32. The arm 19 is extended beyond its pivotal support 18, and the said extension carries an arm 33 having a bent end or hook 33a, nearly or quite in engagement with the upper end portions of the links 28 and 30 for the position of the parts shown in Fig. 1. The arm 19 and the armature 15 are held inthe position,

indicated in ll'ig. 1. by a spring 34 between the lower extension of the arm 19 and the arm 32, and outward motion of the armature 15 away from the tripping coil, is limited by a stop 35 carried by the lower end-of the extension ofthe arm19,whichrestsagainsttheedgeofthe arm '32.

As a result of the construction thus far described, when the armature 15 is drawn towards the magnetic heads 14a of the tripilnl coil.. by energisation of the coil, the bent end 33a of the arm 23, moves the upper ends of the links 28 and 30 to the left sufdciently to move the line of pull on the link 28, through the pivotal connections 27 and 29, to the left of the pivotal connection 3l, thus releasing 'the locking condition of the links and permitting expansion of the spring 26 to move the sleeve 25, and therefore the plunger 11, downwardly to the position indicated in Fig. 3. This movement, it will be understood, takes place very quickly and produces a quick break in the circuit between the lower inner edge of the ring 13 and the extreme upper edge of the chamfercd portion lla of the plunger 1l. thus reducing arcing to a minimum. Any arcing that occurs at this time is further reduced, or entirely suppressed, by the magnetic action of the tripping coil 14, which is effective as a magnetic blow-out,

due to its relation to the breaking or arcing point of the mechanism. The circuit through the trippir/g coil is maintained during the separation of the end of the plunger from the ring 13, to secure th.. magnetic blow-out effect referred to, and the circuit of the tripping coil is subsequently broken by means of the following construction. A second tube of insulating material 36 is suppcrted at its lower end, for the position of the parts shown in Fig. 1, by the annular flange 21 and at its upper end by a clip 37 secured to the lower head 14a of the tripping coil. The tube 36 contains therein a freely movable metal rod 38 engaging a tubular contact 39 at its upper end when the rod 38 is in the position shown in Fig. l. The contact 39 is of the same general construction as the contact 12 and is rigidly supported by the upper end of the tube 36. 'Ihe upper end of the tube 36 is also provided with a cap 40, preferably of insulating material, to protect the parts. The end wall of the cap 40 is preferably perforated and n perforated disc 41 is shown between the cap and the outer end of the contact 39, to prevent the proany flames or burning gases that may be produced by it. The sleeve 22 also holds between its end and the end of the contact 12a, a similar perforated disc 42 for securing the same result with the main breaker. The upper end of the rod 38 is preferably chamfered for the same reason described above for the chamfered portion 11a of the plunger ll. The tube 36 carries a second contact 43 at its lower end, which is in sliding engagement withthe rod 38. Provision is made on the contact 43 for connecting the same by a wire 44 with a tripping circuit, and the lower end of the contact 43 and the said connection are preferably enclosed by a protecting cap 45 of insulating material. The upper contact 39 of the auxiliary breaker is connected by a wire 46 with one terminal of the tripping coll 14, and the other terminal of the tripping coil is connected with a wire 47 to form tbe other connection with the tripping circuit.

The rod 38 has rigidly secured to its lower end arod 48 of insulating material provided near its'v -upper end with an arm 49 engaging one end of a spring 50 the other end of which is connected with a rod 51 having a bent lower end 51a, said rod 51 extending loosely through an aperture provided therefor in the arm 24. The rod 48 is 'rigidly secured at its lower end to a metal rod 52 provided at its upper end with a flange 53 and at its lower end with a flange 54, said rod 52 extending with a sliding ilt through a suitable aperture therefor in the outer endfof the arm 24.

As a result of the construction described, operation of the auxiliary breaker is effected as follows: When the spring 26 moves the plunger 1l from the upper contact 12a. the arm 24 moves freely on the rods 51 and 52 and at this time the spring 50 is under no tension. After the upper end of the plunger ll has left the ring i3. or at about the time it leaves said ring, the bent end 51a of the rod 51 is engaged by the am 24 and further movement outwardly of the arm 24 pinzas the spring 50 under tension which condition continues until the arm 24 engages the ange 54. 'Ihe engagement of the arm 24 with the flange 54, as a result of the arm 24.- being in rapid motion at the time, produces a hammer blow effect on the rod 52 and .therefore on the rod 38, to start the rod 38 in motion downwardly against the friction of the contacts engaging it, and when the rod 38 leaves the contact 39, the spring 50 operates to move the rod 38 rapidly from the end of the contact 39, thus quickly breaking the circuit of the tripping coil, the current flowing in which may be made relatively small in any event by properly proportioning the windings. The flange.53 prevents the rod 38 from being drawn too far from the tube 36 and also serves to move the rod 38 back to the position shown in Fig. 1 when the arm 24 is raised to close the main contacts of the circuit breaker, thus insuring the closure of the contacts of the auxiliary breaker, every time that the contacts of the main breaker are closed.

It will be noted that for the closed condition of the contacts of the circuit breaker, the flanged end a of the sleeve 25 is somewhat above the upper surface of the arm 24, the amount of this separation being determined by a headed stud or studs 55 extending through a clearance opening or openings therefor in the arm 24 and secured to the flanged head 25a of the sleeve 25. The stud or studs 55 thus serve to prevent undue separation between the arm 24 and sleeve 25 and the separation referred to provides that the sleeve 25 shall impart a hammer blow to the arm 24 when the main circuit breaker is released and 'thus effect a positive beginning of the movement of the plunger 1l in the contact 12a against its frictional engagement with said plunger.

After the tripping coil has been actuated and the parts have moved to the position indicated in Fig. 3, opening both the main circuit and the tripping coil circuit, the circuit breaker may read'- ily be reset, or moved to the position shown in Fig. l, by raising the arm 24 and moving the pivotal connection 29 outwardly and around to the right relatively to the pivot connection 31, until the ends of the links 28 and 30 adjacent the pivotal connection 29. rest against the stop 32a in close proximity to the bent end 33a of the arm 33.

The arm 32 is shown as extended downwardly to form a bracket 32h supporting insulated contacts 32e and 32d, for actuation by the arm 35a for the open position of the circuit breaker. These contacts are provided to permit controlling additional circuits by the opening of the circuit breaker, for example where it is desired to use a plurality of the circuit breakers in a dennite sequence of operation to protect an electrical system. each of the circuit breakers may be provided with a tripping coil circuit controlled by the contacts 32e and 32d of another of said breakers, so that the opening of any one of seid circuit breakers will cause the opening of the next one in the sequence and so on.

In Fig. 4 I show a somewhat modified construction of the means employed for breaking the main circuit through the circuit breaker as follows: in this construction the upper end of the plunger lib carries a ring 56 of refractory conducting material, for example carbon, of substantially the same diameter as the plunger. and above the ring 56 there is rotatably or otherwise secured to the upper end of the plunger 11b, a cylindrical extension 57 of refractory nonconducting material. for example porcelain, which is provided with a helical groove or grooves 57a in its outer surface. extending from the ring 56 to the upper end of the extension 57. In this construction the contact 12b which engages the plunger 11b for the closed relation of the circuit breaker, is extended to forman enclcsing tube 12o for the extension 51, the upper end of the tube being enclosed by a cap 58 which is perforated and which preferably clamps a perforated disc 59 between it andthe end of the tube 12e, to permit ready egress of gases due to arcing, without permitting the egress from the tube 12e of burning gases. In this construction the main tube 10 of the circuit breaker supports a sleeve 22h, the outer end of which is of reduced diameter as indicated at 22e. to engage and support the tube 12e. In this construction the contact 12b carries at its inner end a ring 13, preferably of carbon, as and for the purposes above described.

With the construction last described, when the ring 56 is within the ring 13, immediately after tho plunger 11b has moved from engagement with the ring 13, a path of relatively high resistance is maintained between the end of the contact 12b and the end of the plunger 11b, through the rings 13 and 56, and when the ring 56 moves from within the ring 13 to break this path of relatively high resistance, any arcing Athat may result is provided a path of relatively free discharge through the helical groove or grooves 57a to the chamber then formed in the upper end of the tube 12o and through the perforations in the disc 59 and cap 58. It will be observed that this path of discharge is relatively long thus preventing any damage that might otherwise result from burning gases or flame from the arc. A further advantage securedl by this construction is that the arcing path or striking distance between the rings 13 and 56 is much greater at any time during their separated rela- ICE;

tion, than the distance separating them: this provides. for any particular construction of circuit breaker, that the arcing path is greatly increased in length over what it would be with the construction shown in Fig. 1, and also that for any particular length of arcing path found to be necessary or desirable for a particular use, the distance of separation between the plunger and contact can be much reduced from what would otherwise be necessary and the device can be made of correspondingly smaller dimensions. It will further be observed that. although the arcing path is wholly enclosed, it is in contact throughout its length with the metal extension 12o, which rapidly absorbs and radiates the heat resulting from the arcing action, and thus the effectiveness of the device in preventing detrimental results from arcing, is much increased. In other respects the construction of the circuit breaker is the same as above described.

In carrying out my invention, I find it desirable in many cases to provide a plurality of windings in the tripping coil of the circuit breaker construction above described. In certain of these cases I find that a single auxiliary breaker may be employed in a common conductor forming a part or the circuits or an of said windings. in

which cases. the circuit breaker construction shown in Fig. 1 may be employed. In other cas'es I find it desirable to provide circuits for said windings.- that are electrically distinct and .V

the magnetic heads oi' the tripping coil, as shown at lib, is extended to support by a clip 37a, two auxiliary breakers having caps 40a, 40h, said auxiliary breakers being supported at their other ends by a flange 21a, similar to the nange 21, and provided at said other ends with caps 45a, 45h. The windings are provided with terminal wires in the same manner shown in connection with Fig. l, these terminal wires being electrically independent and being shawn for the several auxiliary breakers at 44a, 44h respectively. This modiiled construction is provided with an arm 24a for engaging spring ends 51h, 51e and ilanges 54a, 54h for the two auxiliary breakers respectively, in the same manner and for the same purpose that the arm 24 engages the spring end 51a and the ilange 54 in the construction of Fig. 1. Each auxiliary breaker is of the same construction and operates in the same manner as shown and described in connection with Fig. 1 and the construction and operation of the main circuit breaker is also the same as above described. The relation oi the arm 24a to the auxiliary breakers is the same as described above for the construction shown in Fig. I and insures the closing of the auxiliary breakers each time that the main breaker is closed. In the same manner, the circuit breaker mec-.hanism may be provided withl any desired number oi auxiliary breakers to meet the requirements of any particular case.

While I have shown m'r invention in the particular embodiment above described, it will be understood that 1 do not limit myself to this exact construction as I may employ equivalents known to the art at the time of the tiling oi this application without departing from the scope ot the appended claims.

What I claim is:

l. In a circuit breaker, the combination oi a plunger oi conducting material capable of longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger inA engagement with said main cnntact against the action of said spring, andelectromagnetic mechanism tor moving said devices to releasing position, said electromagnetic mechanism comprising a lever engaging said devices, an armature carried by said lever, and an electromagnet having energizing windings for operating said armature, said windings comprising a plurality of independent tripping coils.

2. In a circuit breaker. the combination oi a plunger of conducting material capable oi longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending t) move said plunger from enagement with said main contact, devices for holding said plunger in engagement with said main contact against the action of said spring, and electromagnetic mechanism for moving said devices to releasing position, said devices comprising a pair oi links pivotally connected to each other and extendingbetween said plunger and a fixed support, said links in their set position having their pivotal connection on vthe opposite side of the line of pull on said links to that assumed by said connection during the releasing operation.

3. In a circuit breaker, the combination oi a plunger oi conducting material capable of longitudinal motion, a main contact for engaging nonsens and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action oi said spring, electromagnetic mechanism for moving said devices to releasing position, and mounting clips connected with and extending from said main contacts.

4. In a circuit breaker, the combination of a plunger oi conducting material capable oi longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action oi' said spring, electromagnetic mechanism i'or moving said devices to releasing posiiion, said devices comprising a pair oi links pivotally connected to each other and extending between said plunger and a fixed support, said links in their set position being adjacent each other with their pivotal connection on the opposite side o! the line of pull on said links to that assumed by said connection during the releasing operation, and said electromaglnetic mechanism comprising a lever engaging said devices, an armature carried by said lever, and an elcctromagnet having an energizing winding for operating said armature, and an arm extending rrom said lever to engage said `links adjacent their pivotal connection to move said links to releasing position when s'aid armature is attracted.

5. In a circuit breaker, the combination oi a no plunger of conducting material capable of longitudinal motion, a main contact for engaging and dlsengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action oi said spring, electromagnetic mechanism for moving said devices to releasing position, said plunger being extended in its closed position beyond said main connector, an arm projecting from the outer end of said plunger, and a sleeve having a ilanged end loosely iltting said plunger extension, said spring being helical and surrounding said sleeve and restrained bythe anged end oi said sleeve and a ilxed support, said devices engaging said sleeve, there being a clearance space between said plunger arm and the adjacent end of said sleeve, whereby on being released said spring imparts a hammer blow to said plunger in a direction to move the same towards its open position.

6. In a circuit breaker, the combination oi a plunger of conducting material capable of longitudinal motion, a main contact ior engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action of said spring,velectromag netic mechanism for moving said devices to releasing position, and electric contact mechanism closed by movement oi said plunger away from said main contact.

7. In a circuit breaker, the combination of a first plunger of conducting material capable of longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices ior holding said plunger in engagement with said main contact against the action oi' said spring, electromagnetic mechanism for moving said devices to releasing position, an auxiliary plunger of conducting material, a break contact for engagementwith said auxiliary plunger, a sliding connector in continuous engagement with sa'd auxiliary plunger, said break connector, auxiliary plunger and sliding contact constituting a part of the circuit of said electromagnetic mechanism, and operating connections between said plungers whereby movement of said iirst plunger moves said auxiliary plunger from engagement with its break contact. C

8. In a circuit breaker, the combination of a ilrst plunger of conducting material capableoi longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action oi' said spring'. electromagnetic mechanism for moving said devices to releasing position, an auxiliary plunger of conducting material, a break contact for engagement with said auxiliary plunger, a sliding connector in continuous engagement with said auxiliary plunger, said break contact, auxiliary plunger and sliding connector constituting a part of the circuit of said electromagnetic mechanism, and operating connections between said plungers whereby movement of said ilrst plunger moves said auxiliary plunger from engagement with its break contact after the circuit through said first plunger has been opened.

9. In a circuit breaker, the combination of a ilrst plunger oi' conducting material capable of longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger ln engagement with said main contact against the action of said spring, electromagnetic mechanism for moving said devices to releasing position, said electromagnetic mechanism including windings comprising a plurality of tripping coils, and a plurality o! auxiliary breakers each .comprising an auxiliary plunger of conducting material, a break contact for engagement with said auxiliary plunger, a sliding connector in continuous engagement with said auxiliary plunger, said break connector, auxiliary plunger and sliding contact constituting a part of 'the circuit oi' one ot said tripping coils, and operating connections between said plungers whereby movement oi said tlrst plunger moves each auxiliary plunger from engagement with its break contact.

10. In a circuit breaker, the combination of a movable switch member, abreak contact. devices tending to move said member away from said contact, means for holding said member in closed position, a winding for electromagnetically releasing said means, and a vented casing entirely enclosing said memberand contact.

vl1.. In a circuit breaker, the combination of a rst movable switch member, a iirst break contact for engagement by said member, devices leasing said means, an auxiliary movable switch member separate trom said first switch member, a second break contact vior engagement by said auxiliary switch member, and devices 'connecting said switch members to open said auxiliary switch member by movement of said tirst switch member.

12. In a circuit breaker, the combination of a nrst movable switch member, a ilrst break contact for engagement by said'member, devices tending to move said member away i'rom said contact, means for holding said member in closed position, a winding for electromagnetically releasing said means, an auxiliary movable switch member separate from said first switch member, a second break contact for engagement by said auxiliary switch member, and devices connecting said switch members to open said auxiliary switch member by movement of said ilrst switch member, said auxiliary switch member and said second break contact constituting a part of the circuit of said winding.

13. In a circuit breaker, the combination of a iirst plunger ot conducting material capable of longitudinal motion,'a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said-main contact, devices for holding said plunger in engagement with said main contact against the action of said spring, electromagnetic mechanism for moving said devices to releasing position, said electromagnetic mechanism including windings comprising a plurality of tripping coils, and a plurality of auxiliary breakers connected with said tripping coils.

14. In a circuit breaker, the combination of a nrst movable switch member, a first break contact for engagement by said member, devices tending to move said member away from said contact, means tor holding saidI member in closed position, a winding for electromagnetically releasing said means, an auxiliary movable switch member separate from said first switchl'member, a second break contact for engagement by said auxiliary switch member, and devices connecting said switch members te open said auxiliary switch. member by movement of said first switch member and to close said auxiliary switch member by closing said first switch member.

15, In a circuit breaker, the combination of a first plunger oi' conducting material capable of longitudinal motion, a main contact for engaging and disengaging said plunger, a main connector in sliding engagement with said plunger, a spring tending to move said plunger from engagement with said main contact, devices for holding said plunger in engagement with said main contact against the action of said spring,

velectromagnetic mechanism for moving said devices to releasing position, said electromagnetic mechanism including windings comprising a plurality of tripping coils, a plurality ot auxiliary breakers connected with said tripping coils, and operating devices connecting said auxiliary breakers with said plunger and opening said auxiliary breakers by opening movement of said plunger and closing said auxiliary breakers by closing movement oi' said plunger.

LLOYD E. KING. 

